| 摘要 |
PURPOSE:To realize higher performance by decreasing the residual stresses of dielectric films. CONSTITUTION:The dielectric material layer of this optical recording medium is the composite body consisting of plural dielectric materials which are different in the directions of the residual stresses. An overcoat layer and under coat layer having extremely less residual stresses can, therefore, be realized. For example, the dielectric layer which generates no deformation at all even if thermal relief of the stress arises after heating up to about 600 deg.C can be manufactured by combining SiO2 having the residual compressive stress and MgF2 having residual tensile stress and using the same as the over coat layer and under coat layer of an optical recording medium. The stresses are offset if the materials having different directions of the residual stresses are used in combination; therefore, the considerable decrease of the residual stresses over the entire part of the dielectric layer is possible and the deformation by heating arises hardly. Namely, the film which has the extremely high mechanical strength for laser impact and hardly breaks down is realized. |
